This invention relates to a volumetric dosing apparatus for pasty material, namely for chopped meat and the like, of the type comprising an adjustable dosing chamber, having a known capacity, which can be automatically and cyclically filled and emptied to form portions having an identical volume.
In the state of the art different apparatuses of this type are known, such as Patent WO 9014578 in which a machine is disclosed which includes a dosing chamber with an inlet and outlet at one of its ends. Said dosing chamber is provided in its interior with a distributor to alternatively communicate said chamber with said inlet and with said outlet and a plunger which can be freely moved by the effect of the pressure exerted by a pasty material introduced in the dosing chamber by a feeder, a pump or the like, through said inlet and said distributor in inlet position. Said plunger free run goes from a first position to a second position which is predetermined by means of an accurately adjustable stop using a worm system which delimits the volume to be dosed. Thereafter, said plunger is driven in the opposite direction by means of compressed air being forced to come back to said first position, moving the dosed volume of pasty material through said distributor in position of communication with said outlet from which it can be collected in a container or become a sausage. Said apparatus has pneumatic means available which raises the whole dosing chamber in order to allow the access of the alternating distributor for its withdrawal, periodical cleaning and/or inspection.
With this arrangement a very good volumetric dosing of the pasty material is achieved but, however, it has the drawback that the whole work of withdrawing the product must be carried out by the plunger of the dosing chamber. When a significantly long outlet duct is required, as in the case stuffing, important friction forces appear along the outlet duct which require an important stress from said plunger, in addition to the fact that as it is relatively far from the outlet mouth, more than one plunger stroke accumulate in said outlet duct, the dosed volume thus losing accurateness. On the other hand, when the machine stops there is always a portion of product which remains within the outlet duct which is very hard to eliminate, making difficult the work of cleaning this part of the apparatus and meaning a possible deficit of the product sanitary quality. In addition, the system for having access to the alternating distributor by raising very large pieces and supporting them in raised position shows several drawbacks, first relatively powerful fluid mechanical means are required for carrying out said operation; and second, any failure in these fluid mechanical means while having access to the distributor can provoke the descent of the supported pieces, which directly involves a risk of an accident for the manipulating worker.
Therefore, an object of this invention is to provide with a volumetric dosing apparatus of this type having means independent from the plunger of the dosing chamber to cooperate in the withdrawal of the product, namely useful for works such as packing and stuffing.
Another object of the invention is to provide with an apparatus of the type referred to capable to fully empty the contents of the outlet duct at each cycle.
Another object of the invention is to provide an apparatus of the type referred to with means of access to the alternating distributor, simple, easy to handle and safe for the worker.
Last, another object of the invention, is to provide with an apparatus of this type having a tubular fitting, interchangeable with other ones having different lengths, which constitutes an external extension of the outlet duct, useful for works such as stuffing, which can be completely emptied, together with this later, at each cycle.
These objects are achieved with an apparatus according to this invention by arranging a piston within the outlet duct capable to move on a run from a first position, prior to the opening of the communication of the distributor in outlet position with said outlet duct, up to a second position at the end of said outlet duct or of an accessory pipe which extends it.
To allow the access to the alternating distributor, it has been arranged within an independent housing of the compression chamber and there exists an hinge-joint between them so that by simply releasing fastening means and tilting by hand the dosing chamber said distributor becomes easily accessible, while the chamber remains idle in an open position.
To facilitate the removal of the pasty material from the interior of the dosing chamber through the alternating distributor, avoiding bends in the ducts and to eliminate hardly accessible comers, the outlet duct has been arranged in a secant position with the housing of the valve body of said distributor so that a passageway opening is formed between them by said secant interference. On the cylindric wall of a valve body which can rotate within said housing, a groove has been arranged according to a secant interference which can coincide with said secant interference of the outlet duct with the housing of the valve body, to allow the passage of said piston within the outlet duct while said valve body is in a position in which the inlet duct communicates with the chamber for stuffing.
These and other characteristics of an apparatus according to the invention, as well as its operation, will result clearer from the detailed description thereof with reference to the drawings appended which are only illustrative of a possible embodiment of this invention, and are not to be purported as limitative. In the drawings appended: